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Geibel N, Bührmann L, Albers L, Schmidtmann M, Weiz A, Müller T. Germaaluminocenes-Masked Heterofulvenes. Angew Chem Int Ed Engl 2024; 63:e202403652. [PMID: 38578658 DOI: 10.1002/anie.202403652] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 03/20/2024] [Accepted: 03/21/2024] [Indexed: 04/06/2024]
Abstract
Germaaluminocenes are formed by salt metathesis reactions of dipotassium germacyclopentadienediides with pentamethylcyclopentadienylaluminum dichloride. The reactivity pattern of these sandwich complexes is determined by the electrophilic central aluminum atom and by the nucleophilic dicoordinated germanium center. Surprisingly, the products formed by reactions with Lewis acids, Lewis bases, amphiphiles and compounds with polar double bonds are those expected from the reaction of a hypothetical aluminagermapentafulvene with these types of reagents. This suggests that germaaluminocenes are synthetic equivalents to these pentafulvenes.
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Affiliation(s)
- Nadeschda Geibel
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
| | - Lukas Bührmann
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
| | - Lena Albers
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
| | - Marc Schmidtmann
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
| | - Alexander Weiz
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
| | - Thomas Müller
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, D-26129, Oldenburg, Germany
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Castellanos E, Benner F, Demir S. Linear, Electron-Rich Erbium Single-Molecule Magnet with Dibenzocyclooctatetraene Ligands. Inorg Chem 2024; 63:9888-9898. [PMID: 38738864 PMCID: PMC11134505 DOI: 10.1021/acs.inorgchem.4c00731] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 04/11/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024]
Abstract
Judicious design of ligand scaffolds to highly anisotropic lanthanide ions led to substantial advances in molecular spintronics and single-molecule magnetism. Erbium-based single-molecule magnets (SMMs) are rare, which is attributed to the prolate-shaped ErIII ion requiring an equatorial ligand field for enhancing its single-ion magnetic anisotropy. Here, we present an electron-rich mononuclear Er SMM, [K(crypt-222)][Er(dbCOT)2], 1 (where dbCOT = dibenzocyclooctatetraene), that was obtained from a salt metathesis reaction of ErCl3 and K2dbCOT. The dipotassium salt, K2dbCOT, was generated through a two-electron reduction of the bare dbCOT0 ligand employing potassium graphite and was crystallized from DME to give the new solvated complex, [K(DME)]2[dbCOT]n, 2. 1 was analyzed through crystallography, electrochemistry, spectroscopy, magnetometry, and CASSCF calculations. The structure of 1 consists of an anionic metallocene complex featuring a linear (180.0°) geometry with an ErIII ion sandwiched between dianionic dbCOT ligands and an outer-sphere K+ ion encapsulated in 2.2.2-cryptand. Two pronounced redox events at negative potentials allude to the formation of a trianionic erbocene complex, [Er(dbCOT)2]3-, on the electrochemical time scale. 1 shows slow magnetic relaxation with an effective spin-reversal barrier of Ueff = 114(2) cm-1, which is close in magnitude to the calculated energies of the first and second excited states of 96.9 and 109.13 cm-1, respectively. 1 exhibits waist-constricted hysteresis loops below 4 K and constitutes the first example of an erbocene-SMM bearing fused aromatic rings to the central COT ligand. Notably, 1 comprises the largest COT scaffold implemented in erbocene SMMs, yielding the most electron-rich homoleptic erbium metallocene SMM.
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Affiliation(s)
- Ernesto Castellanos
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Florian Benner
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
| | - Selvan Demir
- Department of Chemistry, Michigan State University, 578 South Shaw Lane, East
Lansing, Michigan 48824, United States
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Schwarz N, Krätschmer F, Suryadevara N, Schlittenhardt S, Ruben M, Roesky PW. Synthesis, Structural Characterization, and Magnetic Properties of Lanthanide Arsolyl Sandwich Complexes. Inorg Chem 2024; 63:9520-9526. [PMID: 38241036 DOI: 10.1021/acs.inorgchem.3c03374] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/28/2024]
Abstract
A series of trivalent lanthanide sandwich complexes [(η5-C4R4As)Ln(η8-C8H8)] using three different arsolyl ligands are reported. The complexes were obtained via salt elimination reactions between potassium arsolyl salts and lanthanide precursors [LnI(COT)(THF)2] (Ln = Sm, Dy, Er; COT = η8-C8H8). The resulting compounds exhibit classical sandwich complex structures with one notable exception. Characterization was conducted in both the solid state using single-crystal X-ray diffraction and in solution for the Sm compounds using NMR spectroscopy. Furthermore, the magnetic properties of an Er complex were investigated, revealing distinctive single-molecule-magnet behavior characterized by an energy barrier of Ueff = 323.3 K. Theoretical calculations were employed to support and interpret the experimental findings, with a comparative analysis performed against previously reported complexes.
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Affiliation(s)
- Noah Schwarz
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Frederic Krätschmer
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany
| | - Nithin Suryadevara
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Sören Schlittenhardt
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
| | - Mario Ruben
- Institute for Quantum Materials and Technologies, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Hermann-von Helmholtz-Platz 1, D-76344 Eggenstein-Leopoldshafen, Germany
- Centre Européen de Science Quantique, Institut de Science et d'Ingénierie Supramoléculaires, Université de Strasbourg, 8 allée Gaspard Monge, BP 70028, 67083 Strasbourg Cedex, France
| | - Peter W Roesky
- Institute of Inorganic Chemistry, Karlsruhe Institute of Technology, Engesserstrasse 15, 76131 Karlsruhe, Germany
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De S, Mondal A, Giblin SR, Layfield RA. Bimetallic Synergy Enables Silole Insertion into THF and the Synthesis of Erbium Single-Molecule Magnets. Angew Chem Int Ed Engl 2024; 63:e202317678. [PMID: 38300223 DOI: 10.1002/anie.202317678] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2023] [Revised: 01/31/2024] [Accepted: 02/01/2024] [Indexed: 02/02/2024]
Abstract
The potassium silole K2 [SiC4 -2,5-(SiMe3 )2 -3,4-Ph2 ] reacts with [M(η8 -COT)(THF)4 ][BPh4 ] (M=Er, Y; COT=cyclo-octatetraenyl) in THF to give products that feature unprecedented insertion of the nucleophilic silicon centre into a carbon-oxygen bond of THF. The structure of the major product, [(μ-η8 : η8 -COT)M(μ-L1 )K]∞ (1M ), consists of polymeric chains of sandwich complexes, where the spiro-bicyclic silapyran ligand [C4 H8 OSiC4 (SiMe3 )2 Ph2 ]2- (L1 ) coordinates to potassium via the oxygen. The minor product [(μ-η8 : η8 -COT)M(μ-L1 )K(THF)]2 (2M ) features coordination of the silapyran to the rare-earth metal. In forming 1M and 2M , silole insertion into THF only occurs in the presence of potassium and the rare-earth metal, highlighting the importance of bimetallic synergy. The lower nucleophilicity of germanium(II) leads to contrasting reactivity of the potassium germole K2 [GeC4 -2,5-(SiMe3 )2 -3,4-Me2 ] towards [M(η8 -COT)(THF)4 ][BPh4 ], with intact transfer of the germole occurring to give the coordination polymers [{η5 -GeC4 (SiMe3 )2 Me2 }M(η8 -COT)K]∞ (3M ). Despite the differences in reactivity induced by the group 14 heteroatom, the single-molecule magnet properties of 1Er , 2Er and 3Er are similar, with thermally activated relaxation occurring via the first-excited Kramers doublet, subject to effective energy barriers of 122, 80 and 91 cm-1 , respectively. Compound 1Er is also analysed by high-frequency dynamic magnetic susceptibility measurements up to 106 Hz.
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Affiliation(s)
- Siddhartha De
- Department of Chemistry, School of Life Sciences, University of Sussex, BN1 9RH, Brighton, U.K
| | - Arpan Mondal
- Department of Chemistry, School of Life Sciences, University of Sussex, BN1 9RH, Brighton, U.K
| | - Sean R Giblin
- School of Physics and Astronomy, Cardiff University, CF24 3AA, Cardiff, UK
| | - Richard A Layfield
- Department of Chemistry, School of Life Sciences, University of Sussex, BN1 9RH, Brighton, U.K
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De S, Mondal A, Ruan Z, Tong M, Layfield RA. Dynamic Magnetic Properties of Germole-ligated Lanthanide Sandwich Complexes. Chemistry 2023; 29:e202300567. [PMID: 37017588 PMCID: PMC10947301 DOI: 10.1002/chem.202300567] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 04/04/2023] [Accepted: 04/05/2023] [Indexed: 04/06/2023]
Abstract
The first germole-ligated single-molecule magnets are reported, with contrasting properties found for the near-linear sandwich complexes [(η8 -COT)Ln(η5 -CpGe ]- , where Ln=Dy (1Dy ) or Er (1Er ), COT is cyclo-octatetraenyl and CpGe is [GeC4 -2,5-(SiMe3 )2 -3,4-Me2 ]2- . Whereas 1Er has an energy barrier of 120(1) cm-1 in zero applied field and open hysteresis loops up to 10 K, the relaxation in 1Dy is characterized by quantum tunneling within the ground state.
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Affiliation(s)
- Siddhartha De
- Department of Chemistry School of Life SciencesUniversity of SussexBrightonBN1 9QRUK
| | - Arpan Mondal
- Department of Chemistry School of Life SciencesUniversity of SussexBrightonBN1 9QRUK
| | - Ze‐Yu Ruan
- Key Laboratory of Bioinorganic and Synthetic Chemistry of the Ministry of Education School of ChemistrySun-Yat Sen UniversityGuangzhou510006P. R. China
| | - Ming‐Liang Tong
- Key Laboratory of Bioinorganic and Synthetic Chemistry of the Ministry of Education School of ChemistrySun-Yat Sen UniversityGuangzhou510006P. R. China
| | - Richard A. Layfield
- Department of Chemistry School of Life SciencesUniversity of SussexBrightonBN1 9QRUK
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Price CGT, Mondal A, Durrant JP, Tang J, Layfield RA. Structural and Magnetization Dynamics of Borohydride-Bridged Rare-Earth Metallocenium Cations. Inorg Chem 2023. [PMID: 37314885 DOI: 10.1021/acs.inorgchem.3c01038] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/16/2023]
Abstract
The structure and magnetic properties of the bimetallic borohydride-bridged dysprosocenium compound [{(η5-Cpttt)(η5-CpMe4t)Dy}2(μ:κ2:κ2-BH4)]+[B(C6F5)4]- ([3Dy][B(C6F5)4]) are reported along with the solution-phase dynamics of the isostructural yttrium and lutetium analogues (Cpttt is 1,2,4-tri(tert-butyl)cyclopentadienyl, CpMe4t is tetramethyl(tert-butyl)cyclopentadienyl). The synthesis of [3M][B(C6F5)4] was accomplished in the 2:1 stoichiometric reactions of [(η5-Cpttt)(η5-CpMe4t)Dy(BH4)] (2M) with [CPh3][B(C6F5)4], with the metallocenes 2M obtained from reactions of the half-sandwich complexes [(η5-Cpttt)M(BH4)2(THF)] (1M) (M = Y, Dy, Lu) with NaCpMe4t. Crystallographic studies show significant lengthening of the M···B distance on moving through the series 1M, 2M, and 3M, with essentially linear {M···B···M} bridges in 3M. Multinuclear NMR spectroscopy indicates restricted rotation of the Cpttt ligands in 3Y and 3Lu in solution. The single-molecule magnet (SMM) properties of [3M][B(C6F5)4] are characterized by Raman and Orbach processes, with an effective barrier of 533(18) cm-1 and relaxation via the second-excited Kramers doublet. Although quantum tunneling of the magnetization (QTM) was not observed for [3M][B(C6F5)4], it was, surprisingly, found in its magnetically dilute version, which has a very similar barrier of Ueff = 499(21) cm-1. Consistent with this observation, slightly wider openings of the magnetic hysteresis loop at 2 K are found for [3M][B(C6F5)4] but not for the diluted analogue. The dynamic magnetic properties of the dysprosium SMMs and the role of exchange interactions in 3Dy are interpreted with the aid of multireference ab initio calculations.
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Affiliation(s)
- Christopher G T Price
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - Arpan Mondal
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - James P Durrant
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
| | - Jinkui Tang
- State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022, P. R. China
| | - Richard A Layfield
- Department of Chemistry, School of Life Sciences, University of Sussex, Brighton BN1 9QJ, U.K
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